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Liquid Lpg Vs Vapour Lpg - Thoughts?


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Hey guys,

Been looking at converting my falcon to lpg and been getting a few quotes on systems. Now several places tell me that they dont do liquid lpg conversions due to them being unreliable and not being as economical compared to vapour systems. One guy said they burn up 30% faster than petrol.

However ive spoken to a few people and read that the liquid lpg systems are actually better for economy and have a 10% increase in power or something compared to petrol. I had a 20min chat with one mechanic who strongly recommends using liquid lpg but unfortunately not all mechanics share his enthusiam. All mechanics agreed that a vapour system has identical power to petrol.

So seeing that im sick of searching the internet and only finding threads and articles from back in bloody 2005, i must ask is anyone here has any experiences with the liquid lpg systems or owns/knows someone who owns a car using it? And if so what is their feedback?

I was quoted $5960 for liquid lpg and told i should have it serviced once a year for $160 which im comfortable with. I was quoted an average of roughly $3500 (give or take a bit) for vapour lpg conversions. And im happy to pay more for the liquid lpg conversion as long as im not going to have non stop trouble with it as I want this to be long lasting and economical.


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Yeah it's good, used to know a guy who did them. Said he saw 30-40kw gains on HSVs straight out the factory with the liquid setups. Vapor injection is also good, you end up with about the same power as petrol.

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I've owned an EF series 2 on LPG, vapour.

An AU series 3 on LPG, also vapour.

The EF got around 12L/100km, it was super efficient after it was tuned. The tune was $50 :)

The AU gets around 14L/100km, more power and a nicer car, but not so efficient.

My brother got injected LPG for his EF (series 1) and it definitely has more response than a vapour system and similar to better economy than the vapour system. But the vapour systems are cheaper :)

From what i've read on the falcon forums, the injected LPG makes a big difference on the BA onward.

From my experience the main difference is response / power, the vapour systems are a singificant drop. The injected closer to petrol :)

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if your going to convert your car, dont bother, sell it and buy a BA dedicated gas model

they hold their price, but worth it

for all gas conversions

it uses more fuel

and is less efficienct

and it takes longer to fill

and its better for the environment

but the fuel is cheaper so the benefit is cheaper fuel

on avg its about 2 years before you re-coup the costs to fit the LPG system and come out even

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thanks for the feedback guys. i did calculate that after roughly 2 years the money ive saved on fuel will have paid off a vapour injected system and a liquid injected system would take about 4 years. the car only has 112,000km on it so im looking to keep it for a few years still. i have considered selling it, but i do enjoy the car and it suits me well with getting around, being a people mover and having a bit of fun in as well.

the car is a 2004 BA XR8 sedan for those asking. right now the fuel economy isnt the best where its sitting roughly on 15.7km per 100km, but thats the computers calculation. some weeks ill get 400km, other weeks ill get 350km. the tank is only 65L as well which i think is small for a V8.

the main concern i have is that there are people who have raised a lot of issues with the injected liquid lpg systems which is what im mainly trying to suss out here. Ive heard that there can be issues starting the car due to the psi changing while the car is off and the liquified gas vapourizes out of the lines or something. there are several other issues pointed out, but these were from mechanics who dont sell the systems so theres always the chance they were just crapping on about them so id buy one of their systems instead like sales people usually do.

the place im looking at getting the conversion done at is smithy's in bayswater. ive heard good things about them and the guy i spoke to on the phone knows his stuff and spent 20mins explaining the differences between all types of lpg systems. seeing my car is a BA series then i know its a lot easier and common for these conversions to be done. the guy did say hes done conversions on land cruisers, FPV's, big block chevy's, etc.

any more feedback from anyone who has used or knows someone with a liquid lpg conversion would be great.

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That electronic readout is pretty cool. What system does it come with? I'm looking at JTG systems as I've heard they're the best

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By the way I calculated that at my current rate of refilling, I'll be going through 5,971 litres of petrol a year, maybe minus a couple hundred litres for when I don't fill up from empty or when i have a period of not driving.

So if $6000 if the roughly value of 4000 litres of petrol, then that means I'm spending roughly $7000-8000 on petrol per year. In that case, a gas conversion would probably half that amount which would save me a lot of money and hence pay the system off pretty fast.

The only things I'm trying to factor are the proven numbers for litres per 100km and reliability. I know the vapor system is a safer option and cheaper but the liquid system I'm sure I would be happier with provided that it delivers the results as promised and doesn't give me grief

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How many kms u doing? That's a shit load of petrol man I'd be buying a little hatch back if I was using that much fuel

I get about 400km or so from a tank. Most of the fuel i burn is in peak hour traffic every morning and arvo heading to and from work. I have considered getting a hatch for weekdays but then the money ill be spending on insurance, rego and fuel for that wont really be practical IMO. Plus I enjoy my falcon and its the right size car for getting around and doing stuff so if i can get away with lpg saving me that extra money thats the way ill go

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I had to replace the converter on the AU about 3 months ago, cost was close to $500 for the converter.

That was a vapour system, in this case it had a tiny hole in it and needed replacement, I believe the system was about 5 or 6 years old.

I drove the EF for 1.5 or 2 years with no issues, and an old LPG system installed by the previous owner.

Considering the number of kilometres your doing, and if your going to keep the car for quite a while you might want to the injected system. Just do your research because you can tune them :)

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We have the direct injection LPG on our ba xr8 ute... but when you put your foot to the floor it switches it over to petrol. LPG is great on the fords and definitely worth the money. Have not tested how many kms to a tank of lpg yet.

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